1. Field of the Invention
The present invention relates to a power generator.
2. Description of the Prior Art
Recently, various power generators generating electric power by converting vibration energy into electric energy are developed. For example, see a patent document 1 (JP 2011-160548A).
The patent document 1 discloses a power generator as shown in FIG. 15. The power generator includes a main body 200 having a rectangular parallelepiped shape formed by a top plate 240 in which an upper through-hole 280 is formed, a bottom plate 260 in which a lower through-hole 400 is formed and sidewalls 220A, 220B. The power generator further includes an upper coil spring 360 provided on an inner-upper side of the main body 200, a lower coil spring 360 provided on an inner-lower side of the main body 200, an upper steel rod 160 passing through the upper through-hole 280 and coupled with the inner-upper side of the main body 200 through the upper coil spring 360, and a lower steel rod 180 passing through the lower through-hole 400 and coupled with the inner-lower side of the main body 200 through the lower coil spring 360.
An upper end portion of the upper steel rod 160 is fixed to a base and a lower end portion of the lower steel rod 180 is attached to a vibrating body such as an air-conditioning duct. Thus, the main body 200 can be vibrated in an axial direction of the steel rods 160, 180 when the vibrating body is vibrated.
The main body 200 contains a power generating unit 460 having a weight 420 fixed on an inner surface of the main body 200, a magnet 480 supported on the weight 420 in the axial direction of the steel rods 160, 180 through a coil spring 520 provided on the weight 420 and a coil 500 fixed on the inner surface of the main body 200. In such power generating unit 460, the magnet 480 is vibrated in the main body 200 along with a vibration of the main body 200. This makes it possible to displace the coil 500 relative to the magnet 480, thereby generating a voltage in the coil 500 due to the electromagnetic induction.
In such power generator having the above structure, the steel rods 160, 180 act as a guide for a vibration of the magnet 480 while the magnet 480 is displaced in a vertical direction. This makes it possible to convert the vibration of the vibrating body into the vibration of the magnet 480 (the main body 200) in the vertical direction. As a result, the power generating unit 460 can generate electric power.
However, in such power generator having the above structure, the main body 200 is likely to be vibrated not only in the vertical direction but also in other directions. As a result, there is a case where the steel rods 160, 180 are slid (vibrated in a horizontal direction) and respectively contact with the through-hole 280, 400. Such contact decreases transmission efficiency of the vibration from the vibrating body to the main body 200 and results in decreasing power generation efficiency of the power generator.
In addition, in such power generator having the above structure, a height (vertical size) of the main body 200 becomes relatively large. Thus, there is a problem that it is necessary to ensure a large installation space for installing the power generator.